Accessory for an electric power tool

ABSTRACT

An accessory for an electric drill is disclosed as including a dust box for receiving abraded materials produced by an electric drill on a workpiece, the dust box including an internal cavity, a first longitudinal end with a first opening communicating with the internal cavity, an opposite second longitudinal end with a second opening communicating with the internal cavity, and a brush or a disc. When a drill bit of the electric drill is received into the internal cavity of the dust box through the second opening, the brush or disc is releasably engageable with the drill bit for simultaneous rotational movement about a longitudinal axis of the drill bit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/030,992, filed Apr. 21, 2016, which is a 35 U.S.C. § 371 nationalstage entry of PCT/CN2014/074888, filed on Apr. 8, 2014, which claimspriority to HK 13111799.5, filed on Oct. 21, 2013. The entire contentsof the '992, '888, and '799.5 applications are incorporated herein byreference.

FIELD OF THE INVENTION

This invention relates to an accessory for an electric power tool and,in particular such an accessory which may be releasably engaged with anelectric power tool.

BACKGROUND OF THE INVENTION

Dust or debris is produced during operation of some electric powertools, e.g. when drilling holes on a wall or ceiling by an electricdrill. Various types of dust catchers have been devised or proposed foraddressing such a problem. In one type of dust catcher, a container isprovided in which a brush is fixedly engaged. A drill bit of theelectric drill is received through the container and through a hole ofthe brush fixed within the container. Upon rotation of the drill bit(e.g. during drilling into a ceiling), the debris or dust so generatedis received within the container. However, it is found in practice thatwhen using such a dust catcher in drilling holes upwardly (i.e. with thedrill bit pointing upwardly), e.g. when drilling holes in a ceiling,dust falls through the brush onto the user.

In addition, it is difficult for a user of an existing electric drill toaccurately determine whether the drill bit has entered a correctdistance into the workpiece (e.g. a piece of wood, a wall, or aceiling). In order to ensure that the drill bit has not gone too deepinto the workpiece (thus drilling a hole of a length or depth longerthan is required), a user has to deliberately drill firstly a hole ofless than the desired depth, then deepen the hole by drilling in stagesuntil the required depth is reached. Such an operation is cumbersome,inaccurate, and prone to errors.

It is thus an object of the present invention to provide an accessoryfor an electric power tool in which at least one of the aforesaidshortcomings is mitigated, or at least to provide a useful alternativeto the trade and public.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is providedan accessory for an electric power tool, said accessory including ahousing for receiving abraded materials produced by an electric powertool on a workpiece, wherein said housing includes an internal cavity, afirst longitudinal end with a first opening communicating with saidinternal cavity, an opposite second longitudinal end with a secondopening communicating with said internal cavity, and at least onemovable member comprising a plurality of bristles, and wherein when autility part of said electric power tool is received within saidinternal cavity through said second opening, said movable member isreleasably engageable with said utility part of said electric power toolfor substantially simultaneous rotational movement about a longitudinalaxis of said utility part.

According to a second aspect of the present invention, there is providedan accessory for an electric power tool, said accessory including ahousing for receiving abraded materials produced by an electric powertool on a workpiece, and means for releasably engaging said accessorywith said electric power tool, wherein said engaging means is movablerelative to said housing along a rail member including a channel forreleasably receiving a plastic anchor, and wherein said accessoryfurther includes means for setting the maximum distance through whichsaid engaging means is movable relative to said housing.

According to a third aspect of the present invention, there is providedan accessory for an electric power tool with a utility part, saidaccessory including means for releasably engaging said accessory with anelectric power tool with a utility part, and means for setting, whensaid electric tool is engaged with said engaging means, a maximum depthof entry of said utility part of said electric power tool into aworkpiece, wherein said setting means includes means for abutting saidworkpiece to prevent further entry of said utility part into saidworkpiece when said utility part of said electric power tool reachessaid set maximum depth of entry into said workpiece, wherein saidabutting means includes a cartridge member and a rod member movablerelative to each other between an extended configuration and a retractedposition, and wherein said cartridge member is adapted to receive aplug.

BRIEF DESCRIPTION OF THE DRAWINGS

Accessories for an electric drill according to the present inventionwill now be described, by way of examples only, with reference to theaccompany drawings, in which:

FIG. 1 is a front perspective view of an accessory for an electric drillaccording to a first embodiment of the present invention;

FIG. 2 is a rear perspective view of the accessory of FIG. 1;

FIG. 3 is a perspective view showing the accessory of FIG. 1 engagedwith an electric drill;

FIG. 4 is an exploded view of a dust catcher of the accessory of FIG. 1;

FIG. 5A is a side view showing the electric drill positioned relative tothe accessory at a rearmost position;

FIG. 5B is a side view showing the electric drill positioned relative tothe accessory at a front-most position;

FIG. 6 is a front view showing a handle of the accessory in two possiblepositions;

FIG. 7 is an enlarged partial view of the accessory of FIG. 1, showing aclamp for setting the maximum drill movement distance;

FIGS. 8A and 8B are side views showing the clamp of FIG. 7 being movableto adjust the maximum drill movement distance;

FIGS. 9A and 9B show detachment of the dust catcher the accessory ofFIG. 1;

FIGS. 10 and 11 show use of the dust catcher of the accessory of FIG. 1as a stand-alone accessory for an electric drill;

FIG. 12 is a front perspective view of an accessory for an electricdrill according to a further embodiment of the present invention;

FIG. 13 is a rear perspective view of the accessory of FIG. 12;

FIG. 14 is a perspective view showing the accessory of 12 engaged withan electric drill;

FIG. 15 is a rear perspective view showing the accessory of FIG. 12engaged with an electric drill;

FIGS. 16A and 16B show releasable engagement of a drill engagement partwith a rail of the accessory of FIG. 12;

FIGS. 17A and 17B show the drill engagement part engageable at differentpositions on the rail of the accessory of FIG. 12;

FIG. 18 shows the accessory of FIG. 12 with a detachable collar;

FIG. 19 shows a number of plastic anchors;

FIGS. 20A to 20D show steps of setting a maximum drill movement distancefor an accessory for an electric drill according to a still furtherembodiment of the present invention;

FIG. 21 is a perspective view of an accessory for setting a maximumdrill movement distance for an electric drill;

FIG. 22 is an exploded view of the accessory of FIG. 21;

FIG. 23 is a perspective view of a further accessory for setting amaximum drill movement distance for an electric drill;

FIG. 24 is an exploded view of the accessory of FIG. 23;

FIG. 25 is a perspective view of a yet further accessory for setting amaximum drill movement distance for an electric drill;

FIG. 26 is an exploded view of the accessory of FIG. 25;

FIG. 27 is a front perspective view showing a yet further accessoryaccording to the present invention;

FIG. 28 is a rear perspective view of the accessory shown in FIG. 27;

FIG. 29 is an exploded view of the accessory shown in FIG. 27;

FIG. 30 is an enlarged front perspective view of the dust catcher of theaccessory shown in FIG. 27;

FIG. 31 is an exploded view of the dust catcher shown in FIG. 30;

FIG. 32 is a perspective view showing the accessory of FIG. 27 engagedwith an electric drill;

FIG. 33 is a partial perspective view of a still further accessoryaccording to the present invention;

FIG. 34 is an enlarged view of the encircled part W shown in FIG. 33,with an auto-locking sliding lock in an unlocked configuration;

FIG. 35 is a sectional view of the auto-locking sliding lock shown inFIG. 34;

FIG. 36 is an enlarged view of the encircled part W shown in FIG. 33,with an auto-locking sliding lock in a locking configuration; and

FIG. 37 is a sectional view of the auto-locking sliding lock shown inFIG. 36.

DETAILED DESCRIPTION

An accessory for an electric power (such as an electric drill) is shownin FIGS. 1 and 2, generally designated as 100. The accessory 100includes a dust catcher 102 and a drill engagement part 104 which areengaged with each other via a rail 106. The drill engagement part 104 isfixedly engaged with a handle 108 for simultaneous movement, so that auser may hold the handle 108 to move the drill engagement part 104accordingly. The longitudinal axis of an annular collar 110 of the drillengagement part 104 is aligned with the longitudinal axis of the dustcatcher 102, along a same axis A-A.

As shown in FIG. 3, an electric drill 112 with a drill bit 114 isreleasably engaged with the accessory 100 by having a front end of theelectric drill 112 received through and contacting the collar 110. Thedrill bit 114 is received through the dust catcher 102 such that a freeend of the drill bit 114 is flush with an outer longitudinal end 116 ofthe dust catcher 102. When the electric drill 112 is thus engaged withthe accessory 100, the central longitudinal axis of rotation of thedrill bit 114 is aligned with the axis A-A.

As shown in FIG. 4, the dust catcher 102 is shown as including a dustbox 118 for receiving abraded materials produced by the electric drillon a workpiece, e.g. a wall, a ceiling, or a piece of metal. The dustbox 118 is transparent to allow easy observation of its internal cavity.The dust catcher 102 also includes a metal ring 120, a brush holder 122,a first brush 124, a mounting frame 126, a second brush 128, a dust boxcap 130 with the outer longitudinal end 116, and a rubber seal 132. Allthe components (including the metal ring 120, the brush holder 122, thefirst brush 124, the mounting frame 126, the second brush 128, the dustbox cap 130 and the rubber seal 132) are generally cylindrical orannular in shape, each having a respective central longitudinal throughhole. When the dust catcher 102 is properly assembled, a lower surfaceof the dust box 118 constitutes a longitudinal end of the dust catcher102 which is opposite to the outer longitudinal end 116. A drill bit 114may be received through the holes of all these components (all alignedwith one another along a common longitudinal axis), with the free end ofthe drill bit 114 entering the dust catcher 102. through an opening 120a of the metal ring 120 and exiting the dust catcher 102 through anopening 130 a of the dust box cap 130.

The metal ring 120 and the brush holder 122 are fixedly engaged to aninner bottom surface of the dust box 118. The first brush 124 is fixedlyengaged with the brush holder 122. The first brush 124 has a number ofbristles radially formed around a central opening 124 a. The mountingframe 126 has an upper rim 134 and a lower rim 136 joined with eachother by a number of ribs 138. The upper rim 134 of the mounting frame126 is fixedly engaged with a lower surface of the dust box cap 130 toform a confined space containing the second brush 128. The second brush128 is sized and shaped to be freely movable within the confined spacebetween the mounting frame 126 and the dust box cap 130. The secondbrush 128 also has a number of bristles radially formed around a centralopening 128 a. The dust box 118 has an opening 118 a for connection witha suction source (e.g. a vacuum cleaner) to allow sucking out of thecontent in the dust catcher 102.

When the dust catcher 102 is duly assembled, and when the drill bit 114of the electric drill 112 is received into the internal cavity of thedust catcher 102 through the opening 120 a of the metal ring 120, thedrill bit 114 is received through the opening 124 a of the first brush124 and through the opening 128 a of the second brush 128. The drill bit114 is thus releasably engaged with the second brush 128 via the centralopening 128 a. As the first brush 124 is fixed relative to the dust box118, the first brush 124 will remain stationary upon rotation of thedrill bit 114 about its own central longitudinal axis of rotation. Onthe other hand, upon rotation of the drill bit 114 about its own centrallongitudinal axis of rotation, the drill bit 114 is frictionally engagedwith the second brush 128, so that the second brush 128 is brought intosimultaneous corresponding rotational movement about its ownlongitudinal axis, which coincides with the central longitudinal axis ofrotation of the drill bit 114.

During drilling operation, a user may hold the electric drill 112 withone hand and hold the handle 108 of the accessory 100 with another hand.The outer longitudinal end 116 of the dust catcher 102 is then moved toabut a surface of the workpiece (e.g. a wall or a ceiling) to bedrilled. Upon activation of the drill 112, the drill bit 114 is causedto rotate and the user pushes the handle 108 to cause the drillengagement part 104 (and thus the drill 112 engaged with it) to movetowards the dust catcher 102, whereupon a length of the drill bit 114will extend through the opening of the outer longitudinal end 116 of thedust catcher 102 and drill into the workpiece. During rotation of thedrill bit 114, the second brush 128 will be brought into simultaneousrotational movement about the central longitudinal axis of rotation ofthe drill bit 114. In addition, as the second brush 128 is onlyfrictionally engaged with the drill bit 114, the drill bit 114 may moveaxially relative to the second brush 128, towards and away from the dustcatcher 102.

It is found in practice that, with such an arrangement, when using theelectric drill 112 engaged with the accessory 100 to drill a hole into aceiling, dust or other materials produced by the drilling operationwhich falls into the dust catcher 102 through the opening 130 a of thedust box cap 130 will drop on the upper surface of the rotating secondbrush 128 (i.e. the surface of the second brush 128 facing theworkpiece). Only a very small proportion of such dust and abradedmaterials will fall onto a user of the electric drill 112 through theopening 124 a of the first brush 124 and the opening 120 a of the metalring 120, as a very large proportion of such dust and abraded materialswill be forced by the rotating second brush 128 to move, transverse tothe longitudinal axis of rotation of the second brush 128 and towardsside walls 118 b of the dust box 118, and to deposit on an inner lowersurface of the dust box 118, for subsequent disposal. If desired, thedust box cap 130 may be detached from the dust box 118 by twisting thedust box cap 130 relative to the dust box 118, so as to allow thecontent in the dust box 118 to be cleared out.

As shown in FIG. 5A, when the electric drill 112 is engaged with theaccessory 100, a free end 114 a of the drill bit 114 is flush with theouter longitudinal end 116 of the dust catcher 102. The outerlongitudinal end 116 of the dust catcher 102 is planar and is thusadapted to abut a surface of a workpiece, such as a wall surface, aceiling surface or a surface of a piece of metal. When the outerlongitudinal end 116 of the dust catcher 102 abuts the surface of aworkpiece to be drilled, the free end 114 a of the drill bit 114 alsotouches the surface of the workpiece.

As shown in FIGS. 5A and 5B, the drill engagement part 104 is movablealong the rail 106 between the position shown in FIG. 5A in which thedrill engagement part 104 is at an allowed maximum distance away fromthe dust catcher 102 (and in which the free end 114 a is flush with theouter longitudinal end 116 of the dust catcher 102) and the positionshown in FIG. 5B in which a slider 140 of the drill engagement part 104(which is engaged with the rail 106 for relative sliding movement) abutsa clamp 142 on the rail 106, and in which a length of the drill bit 114extends out of the dust catcher 102. The drill engagement part 104 isbiased by a spring (not shown) towards the position shown in FIG. 5A.

As the electric drill 112 is engaged with the drill engagement part 104,to-and-fro movement of the drill engagement part 104 along the rail 106will bring about corresponding to-and-fro movement of the electric drill112 relative to the dust catcher 102. As the outer longitudinal end 116of the dust catcher 102 abuts a surface of the workpiece duringoperation of the drill 112, the length of the drill bit 114 whichextends out of the dust catcher 102 is the depth to which the drill bit114 enters the workpiece (i.e. the depth of the hole formed by the drill112 in the workpiece). It can therefore be seen that the distance abetween the slider 140 and the clamp 142 as shown in FIG. 5A (which maybe termed the “maximum drill movement distance”) is the length of thedrill bit 114 which extends out of the dust catcher 102 when the slider140 is moved to meet the clamp 142 (as shown in FIG. 5B), and is themaximum depth to which the drill bit 114 may enter a workpiece.

To allow the accessory 100 to be used in more varied environments, andas shown in FIG. 6, the handle 108 is pivotable about an axis parallelto the longitudinal axis A-A of the dust catcher 102 between an upperposition 108′ and a lower position 108″.

The accessory 100 includes a mechanism allowing a user to adjust themaximum distance between the slider 140 and the clamp 142 (i.e. themaximum drill movement distance), to thereby adjust the maximum depth towhich the drill bit 114 may enter a workpiece. As shown in FIG. 7, theclamp 142 has an arm 142 a which is pivotable relative to a body 142 bbetween an open position (as shown in FIG. 7) and a closed position inwhich the arm 142 a closes with the body 142 b to form a closed loop. Aninner surface of the arm 142 a has a tooth 142 c which may be receivedin one of a number of cavities 106 a at different positions along therail 106 to lock the clamp 142 at those positions against movementrelative to the rail 106. When the arm 142 a is in the open position,the clamp 142 is slidable on and along the rail 106. By way of such anarrangement, a user may pivot the arm 142 a relative to the body 142 bto the open position, move the clamp 142 along the rail 106 to a desiredposition, and then pivot the arm 142 a relative to the body 142 b backto the closed position to move the tooth 142 c into locking engagementwith the cavity 106 a. at the position, to thereby lock the clamp 142against movement relative to the rail 106. As shown in FIG. 8A, theclamp 142 is moved away from its position as shown in FIGS. 5A and 5Band locked on the rail 106 in a position which is closer to the slider140. It can be seen that the distance b between the slider 140 and theclamp 142 is shorter than the distance a shown in FIGS. 5A and 5B. Inparticular, this distance b is the newly-adjusted length of the drillbit 114 which extends out of the dust catcher 102 when the slider 140 ismoved to meet the clamp 142 (as shown in FIG. 8B), and thenewly-adjusted maximum depth to which the drill bit 114 may now enter aworkpiece.

The dust catcher 102 may be removed from the rest of the accessory 100to form a stand-alone accessory. As shown in FIGS. 9A and 9B, to removethe dust catcher 102 from the rest of the accessory 100, the dustcatcher 102 is pivoted from the position shown in FIG. 9A in which thedust catcher 102 is locked with the rail 106 of the accessory 100,through 90° about an axis parallel to the axis A-A, to the positionshown in FIG. 9B in which the dust catcher 102 is removable from therail 106 of the accessory 100.

When the dust catcher 102 is thus detached from the rest of theaccessory 100, it may be used as a stand-alone accessory for theelectric drill 112, as shown in FIGS. 10 and 11. n A connector cap 143may be removed from the stand-alone accessory and a port adaptor 144 maythen be releasably connected with the stand-alone dust catcher 102 forconnection with a vacuum cleaner VC, so as to provide a suction sourceto the dust catcher 102.

An accessory for an electric drill according to a further embodiment ofthis invention is shown in FIGS. 12 and 13, and generally designated as200. The structure and manner of operation of the accessory 200 aresimilar to those of the accessory 100 discussed above. Thus, only thedifferences between the accessories 100 and 200 are discussed here.FIGS. 14 and 15 show engagement of the electric drill 112 with theaccessory 200.

The accessory 200 has a dust catcher 202 which is operatively associatedwith and connected with a drill engagement part 204 via a rail 206. Thedrill engagement part 204 includes a handle 208 and an annular collar210 which are engaged with each other for simultaneous sliding movementalong the rail 206.

As distinct from the dust catcher 102 of the accessory 100 discussedabove, the dust catcher 202 of the accessory 200 has a dust box 218 witha non-circular transverse cross section, such as a transverse crosssection of a cut-circle shape. A dust box cap 230 is correspondinglyshaped to match the dust box 218. Such an arrangement allows theaccessory 200 to be used closed to the corner or edge of adjoining wallsand/or ceilings, or other workpieces.

In addition, and as shown in FIGS. 16A and 16B, the drill engagementpart 204 is releasably engaged with the rest of the accessory 200 by aclamp 246. More particularly, the clamp 246 has an arm 248 which ispivotable relative to the rest of the engagement part 204 between anopen position (as shown in FIG. 16A) and a closed position (as shown inFIG. 16B). When the arm 248 is at the open position, the drillengagement part 204 is releasable from a slider 240 which is slidablealong and on the rail 206. This allows a user to engage the drillengagement part 204 with the slider 240 in a different orientation,allowing a user to hold the electric drill 112 by his/her left hand andhold the handle 208 of the accessory 200 by his/her right hand foroperating the drill 112.

Moreover, as shown in FIGS. 17A and 17B, the slider 240 has severalrecesses 240 b which allow ready engagement of the drill engagement part204 (via the clamp 246) with the slider 240 at a number of pre-setpositions to adjust the maximum distance between the drill engagementpart 204 and the dust catcher 202.

Furthermore, and returning to FIG. 13, in addition to having a clamp 242which is movable on the rail 206 on the side between the drillengagement part 204 and the dust catcher 202, the accessory 200 has afurther clamp 250 on the rail 206 on a side opposite to the dust catcher202. The clamp 250 also has an arm 250 a which is pivotable relative toa body 250 b between an open position and a closed position (as shown inFIG. 13) in which the arm 250 a closes with the body 250 b to form aclosed loop. Similar to the clamp 142 of the accessory 100 discussedabove, an inner surface of the arm 250 a has a tooth which may bereceived in one of a number of cavities 206 a along the rail 206 toselectively lock the clamp 250 at different positions along the rail 206against movement relative to the rail 206. When the arm 250 a is in theopen position, the clamp 250 is slidable on and along the rail 206. Byway of such an arrangement, a user may pivot the arm 250 a relative tothe body 250 b to the open position, move the clamp 250 along the rail206 to a desired position, and then pivot the arm 250 a relative to thebody 250 b back to the closed position to move the tooth of the arm 250a into locking engagement with the cavity 206 a at the desired position,to thereby lock the clamp 250 at the desired position against movementrelative to the rail 206. Thus, both the clamp 242 and the clamp 250 aremovable along the rail 206 and selectively positionable in a respectivedesired location along the rail 206, to thereby adjust the distancethere-between to thereby adjust the maximum depth to which the drill bit114 of the electric drill 112 engaged with the accessory 200 may enter aworkpiece.

A further purpose of providing the clamp 250 is to adjust the maximumdistance between the drill engagement part 204 and the dust catcher 202.For proper operation of the accessory 200, the distance between thedrill engagement part 204 and the dust catcher 202 should be so arrangedthat when the electric drill 112 is engaged with the accessory 200, thefree end 114 a of the drill bit 114 is flush with an outer longitudinalend 216 of the dust catcher 202. However, electric drills are of varioussizes and drill bits are of various lengths. The clamp 250 is thusselectively lockable in different positions along the rail 206 to adjustthe distance between the drill engagement part 204 and the dust catcher202 to suit the accessory 200 for use with electric drills of differentsizes and electric drills installed with drill bits of differentlengths.

Moreover, the accessory 200 has an ancillary collar 210 a in the generalshape of a letter “C” with a narrow gap. The ancillary collar 210 a issized to be received within and engaged with the collar 210 of the drillengagement part 204. As the collar 210 is fixed and is thus of a fixedinner diameter, it cannot fit electric drills of different sizes. Theancillary collar 210 a may thus be releasably fitted within the collar210 to effectively reduce the inner diameter of the collar 210, so as toallow the accessory 200 to be used in conjunction with an electric drillwith an appropriate cylindrical portion of a smaller diameter.

In addition, the accessory 200 has a mechanism for accurately andquickly positioning the clamp 242 along the rail 206 to adjust themaximum depth to which the drill bit 114 of the electric drill 112engaged with the accessory 200 may enter a workpiece. In thisconnection, a number of elongate plastic anchors 252 used in conjunctionwith drilling holes in walls or ceilings are shown in FIG. 19. Themechanism drill depth adjustment mechanism is suitable (though notexclusively) for setting the maximum drill depth to be the length of aplastic anchor 252.

As shown in FIG. 20A, when the electric drill 112 is engaged with theaccessory 200, the drill engagement part 204 is adjusted such that thefree end 114 a of the drill bit 114 is flush with the outer longitudinalend 216 of the dust catcher 202. It can be seen that the clamp 242 has atongue 242 a facing the slider 240. The slider 240 has a central channel240 a into which one plastic anchor 252 is received. The tongue 242 a ofthe clamp 242 is also receivable into the channel 240 a of the slider240. The clamp 242. is then moved along the rail 206 to a position inwhich the tongue 242 a touches a longitudinal end of the plastic anchor252, as shown in FIG. 20B. The clamp 242 is then locked at that locationon the rail 206 against movement relative to the rail 206, and theplastic anchor 252 is then removed, as shown in FIG. 20C. The drillengagement part 204 is then movable on and along the rail 206 towardsthe dust catcher 202 until the tongue 242 a reaches the end of thechannel 240 a in the slider 240. The distance covered by the drillengagement part 204 during such a movement equals the length d of thedrill bit 114 which extends through the outer longitudinal end of thedust catcher 202, which also equals the length of the plastic anchor252. This mechanism therefore allows a user to easily and accurately setthe drill depth of the accessory 200 to be the length of a plasticanchor 252. By using an elongate member of different lengths (but of awidth receivable within the channel 240 a), different maximum drillmovement distances (and thus different drill depths) can also beaccurately and conveniently set.

A further accessory for an electric power tool (such as an electricdrill) according to the present invention is shown in FIGS. 21 and 22,and generally designated as 300. The accessory 300 includes a handle302, a tool engagement part 304, and a depth setting mechanism 306. Thehandle 302 is engaged with the tool engagement part 304 by a screw 308.The tool engagement part 304 has an annular collar 310 for releasableengagement with a generally cylindrical front part of an electric powertool, e.g. an electric drill. The collar 310 has a number of ridges 312along its inner surface for better gripping of the cylindrical frontpart of an electric drill. When the electric drill is engaged with theaccessory 300, the central axis of rotation of a drill hit carried bythe electric drill lies on an axis R-R.

The depth setting mechanism 306 includes a rod 314 biased by a spring316, a front stopper 318 engaged with a spring-loaded front stopperadjustment button 320, a rear stopper 322 engaged with a spring-loadedrear stopper lock 324, and a spring-loaded rod adjustment button 326.

When the accessory 300 is duly assembled, the front stopper 318 may bemoved along the rod 314 and be locked against movement relative to therod 314. Normally, when the front stopper 318 is located at a certainposition on the rod 314, the spring-loaded front stopper adjustmentbutton 320 is biased by springs 320 a to act on the rod 314 to preventmovement of the front stopper adjustment button 320 (and thus the frontstopper 318 with which it is engaged) relative to the rod 314. Inparticular the front stopper adjustment button 320 has a number ofinwardly extending teeth adapted to be in mesh with a row of teeth 314 aprovided along the rod 314. The front stopper adjustment button 320 maybe pressed (against the biasing force of the springs 320 a) to removeits engagement with the rod 314 (i.e. bringing its out of mesh with theteeth 314 a), thus allowing it and the front stopper 318 with which itis engaged to slide along the rod 314 to a different position, When thefront stopper 318 reaches a desired position on the rod 314, a user mayrelease the pressing force on the front stopper adjustment button 320,whereupon the stopper adjustment button 320 is biased by springs 320 ato act again on the rod 314 (in which the teeth of the front stopperadjustment button 320 return to be in mesh with the teeth 314 a of therod 314), to prevent movement of the front stopper adjustment button 320and the front stopper 318 relative to the rod 314.

The rear stopper 322 is also engaged with the rear stopper adjustmentbutton 324, which is biased by springs 324 a to act on the rod 314. Thestructure and manner of operation of the rear stopper 322 are identicalto those of the front stopper 318 and therefore will not be repeatedhere. It should however be noted that a leg 326 c of the rod adjustmentbutton 326 is received within a cavity 324 b of the rear stopper lock324 such that movement of the rod adjustment button 326 towards or awayfrom an axis T-T brings about corresponding simultaneous movement of therear stopper lock 324. The rear stopper lock 324 has a number ofinwardly extending teeth for engagement with the teeth 314 a along therod 314.

By way of such an arrangement, when in the normal configuration, the rodadjustment button 326 is at a position where it is farther away from theaxis T-T, in which position the teeth within the cavity 324 b of therear stopper lock 324 are in mesh with the teeth 314 a of the rod 314,thus preventing relative movement between the rod 314 and the rear lock324. It should be noted that the axis T-T and the axis R-R are parallelto each other.

To set a maximum depth of drill equalling to a length of a plug to beinserted into the hole formed by an electric drill in a workpiece (e.g.a wall or ceiling) with the accessory 300, the electric drill is firstlyengaged with the accessory 300 by having a cylindrical front part of theelectric drill engaged with the collar 310 such that a drill bitinstalled to the electric drill lies on the axis R-R. The rod adjustmentbutton 326 is then pressed, thus allowing the rod 314 to be movedaxially along the axis T-T. When the rod adjustment button 326 is sopressed, the spring 316 is also allowed to extend to its normal extendedconfiguration. The rod 314 is moved until its front end surface 314 b isco-terminus with the front end of the drill bit. Put another way, therod 314 is moved relative to the rest of the accessory 300 to a positionwhere a line passing through the front end of the drill bit and thefront end surface 314 b is perpendicular to the axis T or the axis R-R.The pressing force on the rod adjustment button 326 is then released andthe rear stopper lock 324 is locked onto the rod 314 against relativemovement there-between. This limits the forward-most position of the rod314.

A plug 328 is then placed in a slot on the rod 314 between the frontstopper 318 and the body portion 326 b, with a first longitudinal end ofthe plug 328 abutting the body portion 326 b. The front stopper 318 isthen moved along the rod 314 until it touches a second oppositelongitudinal end of the plug 328, at which point the front stopperadjustment button 320 is allowed to return to its spring-biased positionto lock the front stopper 318 against movement relative to the rod 314.The plug 328 is then removed from the accessory 300.

When drilling, the drill bit of the electric drill drills into aworkpiece. At the same time, the front end surface 314 b of the rod 314contacts the workpiece and causes the rod 314 to retract backwardrelative to the drill. When the front stopper 318 abuts the body portion326 b, the rod 314 cannot retract further backward and hence theelectric drill cannot drill further into the workpiece, thus signifyingthat the set maximum depth of drill has been reached. After drilling,the spring 316 will extend the rod 314, and the front end surface 314 bof the rod 314 will align again with the tip of the drill bit.

A still further accessory for an electric power tool (such as anelectric drill) according to the present invention is shown in FIGS. 23and 24, and generally designated as 400. The accessory 400 includes aplug cartridge 402 and a rod 404 telescopically engaged with each otherfor relative sliding movement. The rod 404 is engaged with the plugcartridge 402 via a spring 406 and a locking ring 408. The plugcartridge 402 is slidable relative to the rod 404 between a contractedposition in which a front longitudinal end 404 a of the rod 404 touchesan inner surface of a front longitudinal end 402 c of the plug cartridge402 and an extended position in which the front longitudinal end 404 aof the rod 404 is out of contact with the inner surface of the frontlongitudinal end 402 c of the plug cartridge 402 to expose an internalcavity 402 a of the plug cartridge 402 to the outside environment.

This accessory 400 is (fixedly or releasably) attached to an engagementpart (such as one similar to the tool engagement part 304 discussedabove) for releasable engagement with an electric power tool, e.g. anelectric drill (not shown). In particular, the engagement part has acollar which engages a front cylindrical portion of the electric drillsuch that, when the electric drill is engaged with the accessory 400 viathe engagement part, the axis of rotation of the drill bit installed tothe electric drill is parallel to a longitudinal axis M-M of theaccessory 400. It can be seen that the plug cartridge 402 is slidablerelative to the rod 404 along the axis M-M.

To set a maximum depth of drill equalling to a length of a plug to beinserted into the hole formed by an electric drill in a workpiece (e.g.a wall or ceiling) with the accessory 400, the electric drill is firstlyengaged with the accessory 400 via an engagement part by having acylindrical front part of the electric drill engaged with the engagementpart such that the axis of rotation of the drill bit installed to theelectric drill lies on an axis parallel to the axis M-M.

The plug cartridge 402 is then moved away from the rod 404 to expose theinternal cavity 402 a of the plug cartridge 402 which communicates withthe outside environment via a window 402 b. The internal cavity 402 aand the window 402 b of the plug cartridge 402 are each sized and shapedto allow insertion of a plug into the internal cavity 402 a through thewindow 402 b.

A plug is then loaded into the internal cavity 402 a of the plugcartridge 402 through the window 402 b, such that a rear end of the plugcontacts the front longitudinal end 404 a of the rod 404 and a front endof the plug contacts the inner surface of the front longitudinal end 402c of the plug cartridge 402. The position of the accessory 400 relativeto the engagement part is adjusted by moving the accessory 400 axiallyrelative to the engagement part until the front longitudinal end 402 cof the plug cartridge 402 is co-terminus with the free end of the drillbit of the electric drill. Put another way, the position of theaccessory 400 is adjusted such that (a) its longitudinal axis M-M isparallel to the axis of rotation of the drill bit of the electric drilland (b) the free end of the drill bit of the electric drill and thefront longitudinal end 402 c of the plug cartridge 402 lie on a lineperpendicular to the axis M-M.

The plug is then removed from the plug cartridge 402, whereupon the plugcartridge 402 is moved back to the contracted position. In thissituation, the front longitudinal end 402 c of the plug cartridge 402 isnot co-terminus with the front end of the drill bit, but is retractedwith respect to the front end of the drill bit. The distance between thefront longitudinal end 402 c of the plug cartridge 402 and a linepassing through the front end of the drill bit and perpendicular to theaxis M-M is thus the length of the plug and is also the set depth ofdrill.

When drilling, the drill bit of the electric drill drills into aworkpiece, but cannot enter further when the front longitudinal end 402c of the plug cartridge 402 contacts the surface of the workpiece, thussignifying that the set depth of drill has been reached.

A still further accessory for an electric power tool (such as anelectric drill) according to the present invention is shown in FIGS. 25and 26, and generally designated as 500. The accessory 500 includes aplug cartridge 502 and a rod 504 telescopically engaged with each otherfor relative sliding movement. The rod 504 is engaged with the plugcartridge 502 via a spring 506 and a locking ring 508. The plugcartridge 502 is slidable relative to the rod 504 between a contractedposition in which a front longitudinal end 504 a of the rod 504 touchesan inner surface of a front longitudinal end of the plug cartridge 502and an extended position in which the front longitudinal end 504 a ofthe rod 504 is out of contact with the inner surface of the frontlongitudinal end of the plug cartridge 502 to expose an internal cavity502 a of the plug cartridge 52 to the outside environment.

This accessory 500 is (fixedly or releasably) attached to an engagementpart (such as one similar to the tool engagement part 304 discussedabove) for releasable engagement with art electric power tool, e.g. anelectric drill (not shown). In particular, the engagement part has acollar which engages a front cylindrical portion of the electric drillsuch that, when the electric drill is engaged with the accessory 500 viathe engagement part, the axis of rotation of the drill bit installed tothe electric drill is parallel to a longitudinal axis S-S of theaccessory 500. It can be seen that the plug cartridge 502 is slidablerelative to the rod 504 along the axis S-S.

To set a maximum depth of drill equalling to a length of a plug to beinserted into the hole formed by an electric drill in a workpiece (e.g.a wall or ceiling) with the accessory 500, the electric drill is firstlyengaged with the accessory 500 via an engagement part by having acylindrical front part of the electric drill engaged with the engagementpart such that the axis of rotation of the drill bit installed to theelectric drill lies on an axis parallel to the axis S-S.

The plug cartridge 502 is then moved away from the rod 504 to expose theinternal cavity 502 a of the plug cartridge 502 to the outsideenvironment. The internal cavity 502 a is sized and shaped to allowinsertion of a plug into the internal cavity 502 a.

A plug P is then loaded into the internal cavity 502 a of the plugcartridge 502, such that a rear end of the plug P contacts the frontlongitudinal end 504 a of the rod 504 and a front end of the plug Pcontacts the inner surface of the front longitudinal end of the plugcartridge 502. The position of the accessory 500 relative to theengagement part is adjusted by moving the accessory 500 axially relativeto the engagement part until an outer front longitudinal end 502 c ofthe plug cartridge 502 is co-terminus with the free end of the drill bitof the electric drill. Put another way, the position of the accessory500 is adjusted such that (a) its longitudinal axis S-S is parallel tothe axis of rotation of the drill bit of the electric drill and (b) thefree end of the drill bit of the electric drill and the outer frontlongitudinal end 502 c of the plug cartridge 502 lie on a lineperpendicular to the axis S-S.

The plug P is then removed from the plug cartridge 502, whereupon theplug cartridge 502 is moved back to the contracted position. In thissituation, the outer front longitudinal end 502 c of the plug cartridge502 is not co-terminus with the front end of the drill bit, but isretracted with respect to the front end of the drill bit. The distancebetween the front longitudinal end 502 c of the plug cartridge 502 and aline passing through the front end of the drill bit and perpendicular tothe axis S-S is thus the length of the plug P and is also the set depthof drill.

When drilling, the drill bit of the electric drill drills into aworkpiece, but cannot enter further when the outer front longitudinalend 502 c of the plug cartridge 502 contacts the surface of theworkpiece, thus signifying that the set depth of drill has been reached.

The inner surface of the front longitudinal end of the plug cartridge502 is formed with a recess (not shown) shaped and sized to receive areduced head 504 b of the rod 504. The recess is of a depth of around 7mm. On the other hand, the plug P cannot be received within the recess.By way of such an arrangement, when using this accessory 500, themaximum length of a hole allowed to be drilled into a workpiece is thelength of the plug P plus the depth of the recess, such as 7 mm. Thepurpose of such an arrangement is to ensure that the depth of the holedrilled is slightly longer than the length of the plug P, such that theplug P can be fully received within the hole.

A yet further accessory according to the present invention is shown inFIGS. 27 to 29 and generally designated as 600. As a major differencebetween this accessory 600 and the accessories 100, 200 discussed aboveresides in a dust catcher 602 of the accessory 600, the dust catcher 602is discussed in more detail below.

As shown in FIGS. 30 and 31, the dust catcher 602 is shown as includinga dust box 618 for receiving abraded materials produced by an electricdrill on a workpiece, e.g. a wall, a ceiling, or a piece of metal. Thedust box 618 is transparent to allow easy observation of its internalcavity. The dust catcher 602 also includes a mounting frame 626, a disc628, a dust box cap 630 with an outer longitudinal end 616, and a rubberseal 632. The dust box cap 630 and the dust box 618 are pivotallymovable relative to each other about a spindle 635. The mounting frame626, disc 628, dust box cap 630 and rubber seal 632 are generallycylindrical or annular in shape, each having a respective centrallongitudinal through hole. When the dust catcher 602 is properlyassembled, a lower surface of the dust box 618 constitutes alongitudinal end of the dust catcher 602 which is opposite to the outerlongitudinal end 616. A drill bit 114 may be received through the holesof all these components (all aligned with one another along a commonlongitudinal axis), with the free end of a drill bit 614 (see FIG. 32)of an electric drill 612 entering the dust catcher 602 through anopening 618 a of the dust box 618 and exiting the dust catcher 602through an opening 632 a of the rubber seal 632.

The mounting frame 626 has an upper rim 634 and a lower rim 636 joinedwith each other by a number of ribs 638. The upper rim 634 of themounting frame 626 is fixedly engaged with a lower surface of the dustbox cap 630 to form a confined space containing the disc 628. The disc628 is sized and shaped to be freely movable within the confined spacebetween the mounting frame 626 and the dust box cap 630. The disc 628has three sections 628 a formed around a central opening 628 b. The dustbox 618 has an opening 618 b for connection with a suction source (e.g.a vacuum cleaner) to allow sucking out of the content in the dustcatcher 602.

When the dust catcher 602 is duly assembled, and when the drill bit 614of the electric drill 612 is received into the internal cavity of thedust catcher 602 through the opening The drill bit 614 is thusreleasably engaged with the disc 628 via the central opening 628 b. Uponrotation of the drill bit 614 about its own central longitudinal axis ofrotation, the drill bit 614 is frictionally engaged with the disc 628,so that the disc 628 is brought into simultaneous correspondingrotational movement about its own longitudinal axis, which coincideswith the central longitudinal axis of rotation of the drill bit 614.

During drilling operation, the outer longitudinal end 616 of the dustcatcher 602 is moved to abut a surface of the workpiece (e.g. a wall ora ceiling) to be drilled. Upon activation of the drill 612, the drillbit 614 is caused to rotate and the user pushes a handle 608 of thedrill 612 to cause the drill 612 to move towards the dust catcher 602,whereupon a length of the drill bit 614 will extend through the openingof the outer longitudinal end 616 of the dust catcher 602 and drill intothe workpiece. During rotation of the drill bit 614, the disc 628 willbe brought into simultaneous rotational movement about the centrallongitudinal axis of rotation of the drill bit 614. In addition, as thedisc 628 is only frictionally engaged with the drill bit 614, the drillbit 614 may move axially relative to the disc 628, towards and away fromthe dust catcher 602.

It is found in practice that, with such an arrangement, when using theelectric drill 612 engaged with the accessory 600 to drill a hole into aceiling, dust or other materials produced by the drilling operationwhich falls into the dust catcher 602 through the opening 632 a of therubber seal 632 will drop on an inner lower surface 618 c of the dustbox 618. Only a very small proportion of such dust and abraded materialswill fall onto a user of the electric drill 612 through the opening 618a of the dust box 618, as a very large proportion of such dust andabraded materials will be forced by the rotating disc 628 to move,transverse to the longitudinal axis of rotation of the disc 628 andtowards side walls 618 d of the dust box 618, and to deposit on theinner lower surface 618 c of the dust box 618, for subsequent disposal.When in the configuration shown in FIG. 27, the dust box cap 630 islocked by a lock 650 to the dust box 618. If desired, the lock 650(which is carried by the dust box cap 630) may be moved in the directionindicated by the arrow L in FIG. 31 to unlock the dust box cap 630 fromthe dust box 618, so as to allow the dust box cap 630 to pivot relativeto and away from the dust box 618 to allow the content in the dust box618 to be cleared out. The dust box cap 630 may then be pivoted back tothe closed configuration shown in FIG. 27 and the lock 650 be moved in adirection opposite to that shown by the arrow L to lock the dust box cap630 against movement relative to the dust box 618.

A further accessory according to the present invention, being amodification to the accessories 100, 200 and 600 disclosed above, isshown in FIGS. 33 to 37 and generally designated as 700. As a majordifference between this accessory 700 and the accessories 100, 200, 600discussed above resides in a sliding lock 740 of the accessory 700 forsetting the maximum distance through which a handle 708 and an annularcollar 710 (which are engaged with each other for simultaneous movement)are movable along a rail 706 relative to a dust catcher 702 (thussetting the maximum depth of drilling of an electric drill releasablyengaged with the accessory 700), the sliding lock 740 is discussed inmore detail below.

As shown in FIGS. 34 and 35, the sliding lock 740 is mounted on the rail706 for sliding movement along and relative to the rail 706. The rail706 has a row of recesses 742 defined by a row of successive teeth 744.The sliding lock 740 has a lock part 746 and a body part 748 which areslidingly movable relative to each other. The sliding lock 740 is shownin FIGS. 34 and 35 as in an unlocked configuration, in which a lock tip750 of the lock part 746 of the sliding lock 740 is raised above therecesses 742, thus allowing the sliding lock 740 (including both thelock part 746 and the body part 748) to be slid along and relative tothe rail 706.

Turning to FIGS. 36 and 37, such show the sliding lock 740 in a lockingconfiguration, in which the lock tip 750 of the lock part 746 of thesliding lock 740 is received within one of the recesses 742, whereby thesliding lock 740 (including both the lock part 746 and the body part748) is locked against movement relative to the rail 706.

Starting from the locking configuration shown in FIGS. 36 and 37, if auser would like to unlock the sliding lock 740, he/she is to move thebody part 748 towards the lock part 746 (i.e. in the direction indicatedby the arrow G in FIG. 37). Such a movement brings two ramps 754 of thebody part 748 each into contact with a respective pin 756 fixedlyengaged with the lock part 746. Further movement of the body part 748towards the lock part 746 will cause the pins 756 to travel upwardlyalong the ramps 754 to raise the lock tip 750 out of engagement with therecess 742, until each of the pins 756 is received within a respectivetrough 760 on an upper platform 762 of the body part 746. The slidinglock 740 is now in the unlocked configuration shown in FIGS. 34 and 35.

If, for example, after sliding the sliding lock 740 to another positionalong the rail 706, the user now would like to return the sliding lock740 to the locking configuration so as to lock the sliding lock 740against movement relative to the rail 706, he/she is to dislodge thepins 756 from the troughs 760 by sliding the body part 748 away from thelock part 746 in a direction opposite to the direction indicated by thearrow G in FIG. 37. During such relative movement, under the biasingforce caused by the resilience of the lock part 746, the pins 756 of thelock part 746 travel downwardly along the ramps 754 until the lock tip750 is received within one of the recesses 742. The sliding lock 740 isnow in the unlocked configuration shown in FIGS. 36 and 37. It should beunderstood that, due to the resilience of the lock part 746, the lockpart 746 is biased towards the configuration in which the lock tip 750is engaged with one of the recesses 742 of the rail 706.

It should be understood that the above only illustrates and describesexamples whereby the present invention may be carried out, and thatmodifications and/or alterations may be made thereto without departingfrom the spirit of the invention. For example, although the inventionshave thus far been discussed in the context of accessories for electricdrills, it is envisaged that the accessories may be used for otherelectric power tools.

It should also be understood that certain features of the invention,which are, for clarity, described in the context of separateembodiments, may also be provided in combination in a single embodiment.Conversely, various features of the invention which are, for brevity,described in the context of a single embodiment, may also be providedseparately or in any suitable sub-combination.

What is claimed is:
 1. An accessory for an electric power tool, saidaccessory including: a housing for receiving abraded materials producedby an electric power tool on a workpiece, wherein said housing includesan internal cavity, a first longitudinal end with a first openingcommunicating with said internal cavity, an opposite second longitudinalend with a second opening communicating with said internal cavity, andat least one movable member comprising a plurality of bristles, andwherein when a utility part of said electric power tool is receivedwithin said internal cavity through said second opening, said movablemember is releasably engageable with said utility part of said electricpower tool for substantially simultaneous rotational movement about alongitudinal axis of said utility part.
 2. An accessory according toclaim 1 wherein said movable member includes a hole for releasableengagement with said utility part of said electric power tool.
 3. Anaccessory according to claim 2 wherein said hole of said movable memberis frictionally engageable with said utility part of said electric powertool.
 4. An accessory according to claim 1 wherein, during substantiallysimultaneous rotational movement of said movable member and said utilitypart of said electric power tool, said movable member allows axialmovement of said utility part of said electric power tool relative tosaid movable member.
 5. An accessory according to claim 1 wherein saidmovable member is within a mounting frame in said housing, and whereinsaid movable member is freely movable between said mounting frame andsaid first longitudinal end of said housing.
 6. An accessory accordingto claim 1 wherein said housing includes exhaust opening for connectionwith a suction source.
 7. An accessory according to claim 1 wherein saidfirst opening and second opening of said housing are co-axial with eachother.
 8. An accessory according to claim 7 wherein, when said utilitypart of said electric power tool is received within said internalcavity, said first opening and said second opening of said housing areco-axial with said longitudinal axis of said utility part.
 9. Anaccessory according to claim 1 further including means for releasablyengaging said accessory with said electric power tool.
 10. An accessoryaccording to claim 9 wherein said engaging means includes an annularmember releasably engageable with said electric power tool tosubstantially align said utility part of said electric power tool withsaid first opening and second opening of said housing.
 11. An accessoryaccording to claim 10 further including a collar releasably engageablewith said annular member for reducing the internal diameter of saidannular member.
 12. An accessory according to claim 1 wherein saidhousing is generally cylindrical in shape.
 13. An accessory according toclaim 1 wherein said housing is of a transverse cross section of acut-circle shape.
 14. An accessory according claim 9 wherein saidengaging means is movable relative to said housing to vary the length ofsaid utility part of said electric power tool extending out of saidhousing through said first opening of said housing.
 15. An accessoryaccording to claim 14 wherein said engaging means is movable relative tosaid housing along a rail member.
 16. An accessory according to claim 14further including a handle movable simultaneously with said engagingmeans.
 17. An accessory according to claim 16 wherein said handle ispivotable relative to said engaging means about an axis parallel to alongitudinal axis of said housing.
 18. An accessory according to claim16 wherein said engaging means and said handle are releasably engagedwith said rail member.
 19. An accessory for an electric power tool, saidaccessory including: a housing for receiving abraded materials producedby an electric power tool on a workpiece, and means for releasablyengaging said accessory with said electric power tool, wherein saidengaging means is movable relative to said housing along a rail memberincluding a channel for releasably receiving a plastic anchor, andwherein said accessory further includes means for setting the maximumdistance through which said engaging means is movable relative to saidhousing.
 20. An accessory according to claim 19 wherein said engagingmeans is movable relative to said housing between a first position onsaid rail member and a second position on said rail member, wherein thedistance between said housing and said first position is longer than thedistance between said housing and said second position, and wherein saidengaging means is biased towards said first position.
 21. An accessoryaccording to claim 20 further including a stopper selectivelypositionable along said rail member to set said second position.
 22. Anaccessory according to claim 20 wherein a length of said elongate memberis the distance between said first position and said second position.23. An accessory according to claim 20 further including means forselectively adjusting said first position.
 24. An accessory for anelectric power tool with a utility part, said accessory including: meansfor releasably engaging said accessory with an electric power tool witha utility part, and means for setting, when said electric tool isengaged with said engaging means, a maximum depth of entry of saidutility part of said electric power tool into a workpiece, wherein saidsetting means includes means for abutting said workpiece to preventfurther entry of said utility part into said workpiece when said utilitypart of said electric power tool reaches said set maximum depth of entryinto said workpiece, wherein said abutting means includes a cartridgemember and a rod member movable relative to each other between anextended configuration and a retracted position, and wherein saidcartridge member is adapted to receive a plug.
 25. An accessoryaccording to claim 24 wherein said set maximum depth of entry of saidutility part into said workpiece is determined by the distance between afree end of said utility part of said electric power tool and saidabutting means.
 26. An accessory according to claim 25 wherein saidengaging means includes an annular engagement part for releasablyengaging with said electric power tool.
 27. An accessory according toclaim 24 wherein said abutting means is movable relative to saidengaging means.
 28. An accessory according to claim 27 wherein saidabutting means is movable relative to said engaging means along alongitudinal axis of said abutting means.